1. Field of the Invention
This invention relates to display heads for head-up display systems suitable for use in vehicles, especially aircraft.
More particularly the invention relates to such display heads comprising an optical display source, a collimating optical system and a combiner arranged so that in operation the optical display source projects light representing a display, via the collimating optical system, onto the combiner for reflection thereby to provide an observer with an image of the display superimposed on the view of a distance scene through the combiner.
2. Description of Related Art
When used in a confined space, for example, a high performance aircraft cockpit, there is an ever present possibility of the user's head accidentally striking the display head and/or movement of the user's head being restricted by the presence of the display head.